How do you calculate wind uplift per IBC/ASCE 7 for "open" structure 1

[BlastResistant]

The only provision for open structures for Method 2 (components & cladding, h<60')in the ASCE 7 is Eq. 6-25 which appears to be valid for only wind loads acting perpendicular to the surface (walls). Figure 6-5 gives GCpi values for open (and closed and partially enclosed) buildings, but nowhere to be found is a Figure that gives GCp values for open structures. I'm guessing that I'm supposed to use the proper Figure for enclosed/partially enclosed buildings to determine GCp for the appropriate building/roof type and use that in Equation 6-22 with GCpi=0? Or do open structures not have wind uplift?

Thanks.

 

[Ron]

Check figures 6-18 b,c,and d; and 6-19 a, b, and c.....all are used for open structures.

By definition in ASCE 7, components and cladding are not applicable open structures, thus you must use MWFRS coefficients for all parts of an open structure.

 

[BlastResistant]

Thanks for the quick reply Ron. At first I didn't know what the heck you were talking about (I was looking in ASCE 7-02) but now that I'm looking at ASCE 7-05, I get it! I should have clarified that in my neck of the woods the applicable code is still IBC 03/ASCE 7-02, but I think I will use the info in Fig's 6-18 and 6-19 as you point out. I don't think our building dept guys will argue with info from the ASCE 7-05. In fact where I live, those guys won't even notice! Thanks for the useful information.